Sound controlling means



Oct. 2,' 1934. F. W. ELWORTHY V1,975,201

SOUND CONTROLLING yMEANS' Filed Aug. 5, 1933 I N VEN TOR.

ATTORNEYS.

rmemea uct. z, 1934 soUNn coN'rRouJNG MEANS Frederick w. Envoi-thy, Beverly mns, Calif. Application August `5, 1933, Serial No. 683,749

6 Claims.

This invention relates to means for improving the quality of the sound delivered by radio receiving sets.

It is a well known fact that in order to weaken or destroy undesirable sound waves, other sound waves may be produced which interfere with them. If the amplitudes of vibration which are produced between interfering sound waves are equal the effect may be the total mutual destruction of the waves which are caused to interfere with each other.

By this invention means are provided which take advantage of the principle just stated in such a manner as to reduce and nullify to a great extent the sound vibrations which have heretofore emanated from the casing and other parts of a radio apparatus which are adjacent to the loud speaker itself.

It is an object of the invention not only to purify and render more natural the sounds produced by the radio transmitter, but also by eliminating unnecesary and harmful sound vibrations to lengthen the life of the tubes of the transmitting set.

l A further object of the invention is to provide a construction of vradio apparatus which will cause a. flow of cooler air into the casing of a radio receiving set thereby keeping the working tubes at a lower temperature and thus lengthening their working life.

While the invention is more particularly intended for use as an adjunct to radio apparatus it is not confined to such use and may be advantageously used in other situations where it is desired to reduce or eliminate undesirable sound waves. l

A still further object of the invention is to provide a means which will hold sound waves emanating from the loud speaker away from the side and interior walls of the radio cabinet.

Other objects, advantages and featurescf the invention may hereinafter appear.

Referring to the accompanying drawing which illustrates what is at present deemed to be a preferred embodiment of the invention,

Fig. l is a vertical sectional view of a radio receiving set, showing the invention applied thereto.r

Fig. 2 is a section on line 2 2 of Fig. l.

Fig. 3 is a transverse section on line 3 3 of Fig. 2.

Fig. 4 is an elevational view of one of the sound modifying panels.

Fig. 5 is a sectional view on line 5-5 ci Fig. 4.

Figs. 6 and 7 are fragmental elevations of modshaped and additional sound openings are pro- `vided.

Referring in detail to the drawing, the radio casing shown in Figs. 1, 2 and 3 is of a conventional type having a back Wall 11, front wall 12, end walls 12a, oor portion 13 and a cover portion 14 the latter being hinged at 15 to the back wall 11. The sound controlling means provided by the invention consists principally of a plurality of panels, one of which is illustrated in detail by Way of example in Figs. 4 and 5. This panel is shown consisting of side wall portions 16, end walls 17 and a back wall 18, there being opposite to the back wall 18 an open faced portion to deliver the modied sound waves.

Within the panel structure which has just been described are lmounted a. multiplicity of irregularly arranged intersecting walls 19 which combine with each other in such a manner as to produce a multiplicity of irregularly shaped cells 20, 30 these cells each being closed on one side by the back wall 18 and being open at the opposite side. Both the panel casing and the intersecting wall construction which has been described may be made of pasteboard, cardboard or similarymaterial.

The panel shown in Figs. 4 and 5 is designated B and this panel is included in the construction shown in Figs. 1 and 3 where it receives the same designation. The back wall 18 of this panel is @0 directed away from the central portion of the cabinet in order that the open sides of the cells 20 may be positioned to munie the modified sound waves toward the loud speaker S.

Describing the various other sound modifying panels shown in the drawing, next to the cover portion 14 of the cabinet is a transverse panel 21 the back wall 21a of which abuts against and is attached to the inner surface of the cover 14.

At each side of this part of the casing is shown a lOU side panel y22 likewise having a back Wall 22a which abuts against the casing wall. The panels 21 and 22 are thus so arranged that the open sides of their cells are directed toward the interior of the radio cabinet. The lower edges of the panels 22 rest upon the door or transverse partition 23 which walls off the radio set 24 from the main chamber 25 which contains the loud. speaker.

Said chamber'25 is likewise provided with the upper transverse sound control panel 26, the llo lower panel,27, an end panel 28 and the cross panel B which has been described in detail. These panels within the chamber 25 are each arranged with the open sides of their cells directed toward the interior of the chamber 25, the panel B being, as already stated,'positioned with the open sides of its cells directed toward the loud speaker S.

Such of the panels as are located in interiorly spaced relation to the walls of the cabinet, including the inner panels 25a: which are located at the sides of the loud speaker, are preferably provided with sound openings through their back walls. Thus the panel 25a.' is shown provided with the sound openings 25a and the panels B are shown provided with the sound openings 29.

In Fig. 6 is shown amodiiled form of sound control panel wherein the side walls 30 hold in place the intersecting walls 31 and 32 by which rectangular cells 33 are formed. In Fig. 'Z is shown another form of the panel wherein the side walls 35 include between them three sets of intersecting cell-forming walls, these intersecting Walls being designated 36, 37 and 38. By means of these intersecting Walls a multiplicity oi symmetrically arranged hexagonal cells 39 are produced.

Owing to the fact that a multiplicity of cell walls are provided within each of the panels, these cell wallsA produce a great number and variety-,of deected sound waves which interfere with each other in such a manner as to greatlyI lessen the volume of sound produced by the more or less resonant walls of the cabinet. Furthermore these deflected sound waves will be of unequal lengths to such an extent that the deflected Waves will have novibration in any way identical with the original Waves which produced them. The sound-deadening effect thus produced within the walls of the cabinet will prevent or else greatly lessen the sound waves being transmitted loutwardly from the walls which enclose the cabinet. The result of this will be that a pure almost natural tone will be produced by the loud speaker as the sound waves therefrom are-interpreted by the human ear.

In Fig. 8 a modified panel is shown wherein the back wall 22x is provided with large sound openings 45 and smaller sound openings 46. The cell walls 47, 48 and 49 are narrower than the depth of the panel and have openings 50 and 5l beneath them. Some of the cell walls are inclined as shown at 52.

In addition to the sound deadening devices which have already been described. a plurality of sound deadening arches or flaps 55 are arranged as indicated in Figs. 4 and 5. These flaps are preferably formed as narrow strips of pasteboard which connect the intersecting panel walls 19 between the panel backs and the open sides oi the cells 20. vThese sound deadening iiaps may be promiscuously arranged or may be grouped in whatever is found by experience to be the most eil'lcient arrangement. The various shapes, angles and openings with which the sound-interfering flaps, walls and flanges are provided all contribute to the formation of a structure which will eiectively elminiate sound vibrations behind the horn, all of which are undesirable.

A further and `still'more important function of the sound deadening apparatus results from the fact that the cells of the panels receive the sound waves which pass rearwardly through and from the walls of the conical loud speaker. These rearwardly directed sound waves are counteracted reraaoi by the reiiecting waves which are produced when they strike against the walls of the cells of the panels. That is to say interfering sound waves are produced which nullify or inutile the backwardlyv directed sound waves which it is desired to destroy. Hence the waves which are directed from the loud speaker to the ear ci the listener will not be accompanied by any other sounds which would interfere with their naturalness and clearness. In other words the loud speaker directs toward the listener only the set of sound waves received from the transmitter. All echo sounds are eliminated.

The sound deadening panels used must be so arranged that when combined with the loud speaker, a completely enclosed space results, in order that the sound emanating from the conical side of the loud speaker may have no opportunity to escape and interfere with the set of sound waves delivered from the inner surface of the loud speaker. The apparatus is rendered still more eiicient because of the pasteboard or like material used to construct the panels being of a soft, porous, sound deadening character.

Asis well shown in Figs. l, 2 and 3, in general, the sound-deadening cells are made up of pockets having cross-sectional dimensions greater than their depth. Pockets or tubes which are a great deal deeper than their transverse dimensions will act as resonators, but the cells provided by -tbs 10d invention are, on the contrary, designed to deaden and eliminate all sounds except those delivered by the horn itself.

I claim:

i. In an apparatus of the kind described, the il@ combination with a. radio receiving cabinet and a loud speaker associated therewith, of a sound modifying panel located within said cabinet, said panel having a series of sound deecting cells which open out at one face thereof, said cells ma having cross-sectional dimensions greater 111m their depth. f

2. In an apparatus of lthe kind dcribed, the

combination with a radio receiving cabinet .mw

a loud speaker associated therewith, of a soun la@ modifying panel located within-said cabinet, said panel having aback wall and a 'multiplicity of sound-modifying cells overlying said back wall and having open sides directed away from said back wall, said cells having cross-sectional dimensions greaterthan their depth.

3. In an apparatus of the kind described, the combination with a radio receiving cabinet and a loud speaker associated therewith, ci a sound modifying panel located within said cabinet, said in said cabinet, said panels formed independently lo of the walls of the cabinet having back w and a multiplicity of cells with open sides which are directed away from said back walls, said panels being positioned within said cabinet with their back walls overlying the inner surfaces of the M5 walls of said cabinet.

5. In an apparatus of the kind described, the combination with a walledain compartment, and sound producing means therewithin, of a pllity of panels positioned to overlie the inner aces B5@ Isii of the walls of said compartment, said panels each having formed independently of the walls of the cabinet directed 6.Ina

with ab and a multiplicity of cells with open sides toward the interior of the compartment. sound muling panel. the combination ack wall, side walls and intersecting cell bridging seid eene between their open' eideeend the back o! the panel. i y

FREDERICK w. ELWOR'I'HY. 

